This invention relates to a motionless mixer to blend a flowable material (hereafter fluid). The mixer, which may be supported in a tube, first divides the flowing fluid into core and fringe streams by means of channels and thereafter guides the core stream into a boundary zone and the boundary stream into a core zone.
A mixer of the above-outlined type is known and is disclosed, for example, in German Offenlegungsschrift (application published without examination) No. 1,901,281. The mixer shown in that publication comprises a bulky structural component which contains obliquely oriented ports (channels) that connect the core zone at the flow inlet side with the fringe zone at the outflow side and connects the fringe zones at the inflow side with the core zone at the outflow side. The single-piece mixer block thus has a three-dimensional geometry which is complex and expensive to manufacture.